It is proposed to purchase an Evans & Sutherland PS 340 Color Graphics System to be installed in the computing center of the Department of Chemistry at Indiana University. This instrument will be used to display and manipulate molecular structures in three-dimensional representations using raster graphics for space filling models and vector graphics for skeletal models. The display of topological details of the molecular environment can be used by synthetic and mechanistic chemists to predict or rationalize chemical reactivity. Quantum mechanical and molecular mechanical, computer programs can be used in the associated computer to determine the relative energetics of various interactions and orientations visually displayed with the molecular graphics system. Applications will be in a variety of research programs including the structure and function of proteins and other biopolymers, drug design and the synthesis of natural products.